Process and agents for opening paper constructions

ABSTRACT

The present process is for opening paper constructions or structures, such as the marginal edges of envelopes, by treating a portion with a sensitizing agent which comprises an alkyl sodium sulfate, thereafter applying a developing agent comprising a strong organic acid to the sensitized portion, heating the developed portion to degrade it and thereafter applying mild mechanical action to remove the degraded portion.

United States Patent 1191 Whitman 1 June 11, 1974 [54] PROCESS ANDAGENTS FOR OPENING 1,646,177 10/1927 Ullom 156/344 PAPER CONSTRUCTIONS2,052,884 9/1936 Leatherman 156/344 2,866,589 12/1958 Zaker 229/51 TSInventor: Nelson ma Lincoln, Mass- 3,006793 10/1961 Wheeler 117/44 [73]Assignee: Thor Inc. New York NIY 3,062,749 11/1962 Herrllng 252/170 [22]Filed: 1971 Primary ExaminerGeorge F. Lesmes [21] Appl. No.1 2,Assistant Examiner-Ellis Phillip Robinson Related Application Datagttgrrgeliygxigent, 0r Firm-Holland, Armstrong, Wilkie [62] Division ofSer. No. 28051, April 13. 1970. Pat. No.

52 US. 01. .Q 156/344, 53/381, 117/76 P, [571 ABSTRACT 51 I Cl I 17/156/247 229/ 32 5 33 The present process is for opening paperconstructions 1 'l i P or structures; such as the marginal edges ofenvelopes, 8] g 1 a f by treating a portion with a sensitizing agentwhich 8/l4 6 52/90 f 53/381) comprises an alkyl sodium sulfate,thereafter applying t l 344 a developing agent comprising a strongorganic acid to the sensitized portion, heating the developed portion todegrade it and thereafter applying mild mechanical [56] References cuedaction to remove the degraded portion.

UNITED STATES PATENTS 1,41 1.077 3/1922 Balogh 229/85 22 Claims, NoDrawings 1 PROCESS AND AGENTS FOR OPENING PAPER CONSTRUCTIONS Thispatent application is a division of US. Pat. application Ser. No.28,051, filed Apr. 13, 1970, said US. Pat. application Ser. No. 28,051is now US. Pat. No. 3,677,460.

DESCRIPTION OF THE INVENTION The present invention is directed to aprocess for opening paper constructions and the agents to be used insaid process. The process will be described in connection with theopening of paper envelopes but it will be understood that the inventionis not limited to this use and may be used to sever or open other paperobjects.

A principle object of this process is to open three sides of envelopeswithout damaging the contents thereof. The system is designed to dealprimarily with business return envelopes which usually contain checksand identifying business machine cards, although tramp metal enclosuresare also commonly found in such envelopes.

A number of envelope openers are on the market, but they are primarilymechanical. While these are satisfactory for opening one side of anenvelope, they are not satisfactory when used to open three sides sincethey must usually cut off about 1/16 of an inch of the envelope to takecare of misalignment in the machine. In making this deep cut, theenclosures may be damaged. The paper shavings also accumulate rapidly atthe preferred opening rate of 500 envelopes per minute and this poses adisposal problem.

The present invention comprises a controlled chemical degradation of theedges of the envelopes followed by mild mechanical action to open thedegraded edges with a minimum of paper scrap. The several steps of theprocess may be performed by manual control or they may be automated toany desired degree.

An object of the present invention is to provide a controlled chemicalprocess for degradation of paper.

An object of the present invention is to provide a chemical process foropening three sides of an envelope without damaging the contentsthereof.

Another object of the present invention is to provide agents which canbe used in the degradation and opening of paper structures.

These and other objects will occur to those skilled in the art uponreading the specification and appended claims or will occur upon actualuse of the invention in practice.

The present invention is an improvement over chemical degradationprocess described in such patents as U. S. Pat. No. 2,866,589 issued toL. F. Zacker on Dec.

' 30, 1958 and U.S.,Pat. No. 2,801,745, issued to L. W.

Piester on Aug. 6, 1957, and it relates to a process in which acontrolled chemical degradation of a portion of a paper construction,such as an envelope, causes rupture and opening of the treated portionsupon application of mild mechanical action.

The process in its broadest context involves application of asensitizing agent to the portion to be opened followed by application ofa developing agent. Heat is thereafter applied to release the degradingchemical from the developed sensitizing agent and mild mechanical actionremoves the degraded portion from the structure.

The preferred sensitizing agent comprises an alkyl sodium sulfate. Thelower molecular weight alkyl compounds such as n-propyl, hexyl anddodecyl compounds are preferred over the higher weights. One example ofa higher molecular weight compound is sodium lauryl sulfate which isavailable in the trade in Stepanol WA and Duponol WAQ. The compound ofchoice is n-propyl sodium sulfate. It may be present to the extent of 10percent in an isopropyl alcohol solution which may also comprise about10 percent water. Aqueous solutions, however, may be used if weakeningof the paper is not objectionable. When applied to the paper beforemanufacture of the envelope it has found desirable to have 2 percent ofa rewetting agent and a small amount of suitable viscosity controlagents in the solution. A suitable rewetting agent is nonylphenol-10-'ethoxylate, such as Tergitol NPX, sold by Union Carbide.

If the sensitizing agent is to be applied after the envelope ismanufacturedbut prior to mailing, the viscosity control agents may bedispensed with. A water solution of the sensitizing agent can be alsoused in place of the preferred isopropyl alcohol solution.

Application of the agent after mailing calls for use of a wetting agentin place of the rewetting agent described above. Sodium dioctylsulfosuccinate or a linear alcohol ethoxylate, such as found in Tergitol15-- 8-7, sold by Union Carbide, may be used.

The sensitizing agent may be printed onto the envelope blank prior tofolding. This requires printing a band at least 4; inch wide to insurethat the edge of the folded envelope is included on the band. A numberof printing processes may be used including felt pad, flexographicletter press, and simulated gravure in flexographic.

When applied after envelope manufacture the agent may be applied byroll, spray or pad to the edges of the envelope. The paper may be coatedon the inside with a water repellant composition. Use of such a coatingprovides a better control of the developing agent which is applied tothe sensitized portion.

Application of the developing chemical is an important step in theoverall process. Addition of too much retards the time cycle and isaccompanied by potential degradation of the enclosures. Addition of toolittle will not open the envelope without serious charring occur ring toboth the envelope and enclosures. It has been found that-satisfactoryoperation requires the addition of about 0.5 to 2.0 milligrams of asolution of 10 percent oxalic acid in water to each inch of envelopeedge (24-lb kraft or white paper) that has been saturated with thesensitizing chemical system. Application by spray, roll or pad methodsmay be used. Other strong organic acids as acetic acid, may also be usedin equivalent quantity.

After application of the developing agent the treated portion may bedried. It has been found possible to dry the portion satisfactorily byimpinging air heated to C and flowing at a rate of 1,300 ft. per minuteupon the envelope edge at a 45 angle for 30 seconds. Exposures of up toone minute do not cause degradation. Use of dried edges insures betteruniformity and less potential thermal damage, although the edges may beleft wet, if desired.

The treated portion is then heated to hydrolyze the sodium alkyl sulfateto the free alcohol which evaporates quickly leaving behind freesulfuric acid in small quantities as well as the salt of the organicacid. The acid degrades the paper in a controlled manner. Exposure forseconds to infrared radiation by holding the edges one inch from adomestic stove heating element or one inch from a quartz tube withtungsten filament rated at 80 watts per inch has proven satisfactory.

After degradation the edges may be removed by mild mechanical action. Arotating nylon filament brush has .been successfully employed. It isalso desireable to provide some ventilation to dispose of the removedpieces.

While the invention has been described in connection with the opening ofthree edges of an envelope, it

will be understood that the invention may be used to open less than thethree edges.

It can be seen from the foregoing that the present process provides asimple, controlled chemical process for opening paper structures withoutdanger of damage to the contents therein and without scrap disposalproblems associated with more conventional mechanical procedures.

As various changes may be made in the form, construction and arrangementof the parts herein without departing from the spirit and scope of theinvention and without sacrificing any of its advantages, it is to beunderstood that all matter herein is to be interpreted as illustrativeand not in a limiting sense.

Having thus described my invention, 1 claim: I

l. A process for opening a portion of a paper envelope, consisting of l)applying a chemical sensitizing agent comprising an alkyl sodium sulfateto a predetermined portion adjacent at least one edge of said envelope,(2) applying a chemical developing agent comprising an organic acidselected from the class consisting of oxalic acid and acetic acid tosaid predetermined portion to release a degrading agent from thedeveloped sensitizing agent to degrade said predetermined portion, saiddegrading agent comprising sulfuric acid of sufficient concentration todegrade the paper, (3) heating said developed sensitized portion, and(4) applying mild mechanical action to the developed sensitized portion.

2. A process as claimed in claim 1 in which said sensitizing agentcomprises a lower molecular weight alkyl sodium sulfate.

3. A process as claimed in claim 1, in which said sensitizing agentcomprises n-propyl sodium sulfate.

4. A process as claimed in claim 1 in which said sensitizing agentcomprises about a 10 percent solution of n-propyl sodium sulfate.

5. A process as claimed in claim 4 in which said solution comprises amajor amount of isopropyl alcohol.

6. A process as claimed in claim 1 in which said developing compoundcomprises oxalic acid.

7. A process as claimed in claim 1 in which said developing compoundcomprises a 10 percent solution of oxalic acid.

-8. A process as claimed in claim 1 wherein said sensitizing agentcomprises a higher molecular weight alkyl sodium sulfate.

9. A process as claimed in claim 1 wherein said sensitizing agent issodium lauryl sulfate.

10. A process as claimed in claim 1 in which said developing agent isacetic acid.

11. A process as claimed in claim 1 in which said predetermined portionis a zone along a plurality of edges.

12. A process for opening a portion of a paper envelope, to which achemical sensitizing agent comprising an alkyl sodium sulfate has beenapplied to a predetermined portion adjacent at least one edge of saidenvelope, said process consisting of steps of: (1) applying a chemicaldeveloping agent comprising an organic acid selected from the classconsisting of oxalic acid and acetic acid to said predetermined portionto release a degrading agent from the developed sensitizing agent todegrade said predetermined portion, said degrading agent comprisingsulfuric acid of sufficient concentration to degrade the paper, (2)heating the developed sensitized portion, and (3) applying mildmechanical action to the developed sensitized portion.

13. A process as claimed in claim 12 in which said sensitizing agentcomprises a lower molecular weight alkyl sodium sulfate.

14..A process as claimed in claim 12 in which said sensitizing agentcomprises n-propyl sodium sulfate.

15. A process as claimed in claim 12 in which said sensitizing agentcomprises about a 10 percent solution of n-propyl sodium sulfate.

16. A process as claimed in claim 15 in which said solution comprises amajor amount of isopropyl alcohol.

17. A process as claimed in claim 12 in which said developing compoundcomprises oxalic acid.

18. A process as claimed in claim 12 in which said developing compoundcomprises a 10 percent solution of oxalic acid.

19. A process as claimed in claim 12 in which said developing agent isacetic acid.

20. A process as claimed in claim 12 in which said predetermined portionis a zone along a plurality of edges.

21. A process as claimed in claim 12 wherein said sensitizing agentcomprises a higher molecular weight alkyl sodium sulfate.

22. A process as claimed in claim 12 wherein said sensitizing agent issodium lauryl sulfate.

I 4 I JNITED STATES PATENT OFFICEO CERTIFICATE OF CORRECTION Patent No.3, 816, 213 Dated II I 1 1mm NELSON WHITMA N It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Column 2, line 5, cancel the comma and substitute ---and--.

Column 2,' line 5, cancel "and dodecyl".

Column 2, line 8, after "sulfate" insert ---which is a dodecyl compoundand---.

Signed and sealed this 15th day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents

2. A process as claimed in claim 1 in which said sensitizing agentcomprises a lower molecular weight alkyl sodium sulfate.
 3. A process asclaimed in claim 1, in which said sensitizing agent comprises n-propylsodium sulfate.
 4. A process as claimed in claim 1 in which saidsensitizing agent comprises about a 10 percent solution of n-propylsodium sulfate.
 5. A process as claimed in claim 4 in which saidsolution comprises a major amount of isopropyl alcohol.
 6. A process asclaimed in claim 1 in which said developing compound comprises oxalicacid.
 7. A process as claimed in claim 1 in which said developingcompound comprises a 10 percent solution of oxalic acid.
 8. A process asclaimed in claim 1 wherein said sensitizing agent comprises a highermolecular weight alkyl sodium sulfate.
 9. A process as claimed in claim1 wherein said sensitizing agent is sodium lauryl sulfate.
 10. A processas claimed in claim 1 in which said developing agent is acetic acid. 11.A process as claimed in claim 1 in which said predetermined portion is azone along a plurality of edges.
 12. A process for opening a portion ofa paper envelope, to which a chemical sensitizing agent comprising analkyl sodium sulfate has been applied to a predetermined portionadjacent at least one edge of said envelope, said process consisting ofsteps of: (1) applying a chemical developing agent comprising an organicacid selected from the class consisting of oxalic acid and acetic acidto said predetermined portion to release a degrading agent from thedeveloped sensitizing agent to degrade said predetermined portion, saiddegrading agent comprising sulfuric acid of sufficient concentration todegrade the paper, (2) heating the developed sensitized portion, and (3)applying mild mechanical action to the developed sensitized portion. 13.A process as claimed iN claim 12 in which said sensitizing agentcomprises a lower molecular weight alkyl sodium sulfate.
 14. A processas claimed in claim 12 in which said sensitizing agent comprisesn-propyl sodium sulfate.
 15. A process as claimed in claim 12 in whichsaid sensitizing agent comprises about a 10 percent solution of n-propylsodium sulfate.
 16. A process as claimed in claim 15 in which saidsolution comprises a major amount of isopropyl alcohol.
 17. A process asclaimed in claim 12 in which said developing compound comprises oxalicacid.
 18. A process as claimed in claim 12 in which said developingcompound comprises a 10 percent solution of oxalic acid.
 19. A processas claimed in claim 12 in which said developing agent is acetic acid.20. A process as claimed in claim 12 in which said predetermined portionis a zone along a plurality of edges.
 21. A process as claimed in claim12 wherein said sensitizing agent comprises a higher molecular weightalkyl sodium sulfate.
 22. A process as claimed in claim 12 wherein saidsensitizing agent is sodium lauryl sulfate.